Big pin 750 ebox on a small pin motor?

My small pin ebox has seen better days, and a local has a really nice looking ebox from a big pin. Are they interchangeable without damaging the small pin motor? Small pin stator ok? Will timing get advanced and will max rpm increase?

I ended up using the stock 650 flywheel and electronics for the 750 swap. It worked nicely because 1 - the X2 I got is in prestine condition with excellent electronics. 2 - Everything fit stock-like a glove. 3 - Lighter flywheel by ~3 lb. 4. No rev limiter that I know of. 5 More advanced timing curve than 750 sp motor.

My 750 swapped X2 is almost ready for test run - just awaiting flame arrester adapters and hope fitment is good.